* May 18, Sunday -- About 50 student drivers for the Unitrans bus system, which serves UC Davis and city of Davis, will compete in a bus "roadeo." Drivers will demonstrate their skills over a course with 10 different tests. The top five winners will be eligible to compete with drivers from seven other transit agencies in a regional event in September. The UC Davis event will run from 9 a.m. to noon in campus parking lot 53 on West Health Science Drive, south of Huchison Drive. Unitrans -- with about 160 drivers and 45 buses -- is believed to be the largest public transit service run by students in the United States. Drivers, who must obtain a Class B commercial license with a passenger endorsement, receive 15 hours of classroom instruction and 25 hours of training behind the wheel.